Abstract:The high-performance nanomaterials industry is going to need to improve its "e-factor" in order to economically penetrate a wide variety of markets, and at the same time deliver on its promise of environmental benefit. Here is a glimpse at some ONAMI research and commercialization efforts in this direction.

October 4th, 2007

Nanomanufacturing - How to Make it Lean and Green

An occasionally cynical friend of mine once commented that the problem with MEMS was that it mostly delivered "ten dollar solutions to one dollar problems". Though this was a while ago, the criticism had a good measure of validity and explained in part why MEMS was slower to catch on than its early enthusiasts expected. Today, with the way paved by some true "killer apps" (like inkjet and DLP), better value propositions and availability of standard processes/equipment/design tools/foundries the situation is much improved.

Nanotechnology (which mostly means nanomaterials) has its own related issues. I heard a presentation today (a good one) by a company that produces or is developing grades of carbon nanotubes ranging from $50/g (for a somewhat mixed grade of material with residual catalyst impurities) to $200,000/gram for the ultimate in selectivity and purity. It is somewhat doubtful that the space elevator cable can afford the former price, but not doubtful at all that the higher figure is out of the question. Those familiar with the fabrication details of nanomaterials know that achieving high purity and uniformity is difficult and expensive.

A related problem that nanomaterials (especially the purer, higher performance ones) and other high-tech products (such as microprocessors and pharmaceuticals) have in common is a very high "E-factor" - the ratio of the mass of waste (i.e. not in final product) material used to produce a product to the mass of the final product itself (concept first articulated by green chemistry pioneer Roger Sheldon of the Delft University of Technology). For typical (not extreme cases) pharmaceuticals, this can be 25 to 100, and for microprocessors it is over 1000 (over 10,000 if you count the DI water). For reasonably purified nanomaterials such as dendrimers or functionalized metal nanoparticles, the E-factor is closer to 1,000,000. Multistep reactions with low yields and multiple washing steps for purification are among the key reasons for this.

From the very beginning of ONAMI (and long before that, on the part of many of our research members) we've been intrigued by these problems, and working on them under the auspices of our 30-investigator Safer Nanomaterials and Nanomanufacturing effort ( http://greennano.org ). "Thrust Area 2" of SNNI is "Greener Manufacturing of Engineered Nanoparticles" and it has been getting terrific results from green chemistries for particle growth and ligand attachment, diafiltration for size selection and purification, and the use of laminated microchannel reactors for precision control and high-rate continuous flow (not sequential batch) production.

Now, after a couple of years of focused research, we have two promising spinout/gap fund companies that are taking these technologies to market.

Dune Sciences ( http://www.dunesciences.com ) is developing custom nanoparticle solutions for strategic partners, and also offering for sale their very useful Smart Grids™ for improved TEM characterization. NanoBits™ ( http://www.nanobits.com ) develops custom micro-reactors for specialty chemical manufacturers. Besides being the best way to manufacture nanoparticles, this low-cost and flexible laminated micro-reactor platform is delivering value today for economically valuable reaction steps that cannot be safely or successfully accomplished in a batch format.

Finally, for the last two years in March, we've been convening the SNNI project stakeholders and larger green nano community at the ONAMI Safer Nano conference. By popular demand, we'll be back again in 2008, but under the new name ONAMI Greener Nano. If these topics are interesting to you, why don't you join us March 10-11? Watch http://greennano.org for the coming details.